Practice the problems of Math in Focus Grade 5 Workbook Answer Key Chapter 9 Multiplying and Dividing Decimals to score better marks in the exam.
Math in Focus Grade 5 Chapter 9 Answer Key Multiplying and Dividing Decimals
Math Journal
Solve. Show your work.
Question 1.
James has a square piece of paper. He wants to cut it into 20 strips of equal width. He says This piece of paper is about 48 centimeters wide.’ How can he find out the width of each strip without measuring? Is this width accurate?
Answer:
2.4 centimeter wide.
Explanation:
By dividing the 48 cm in to 20 equal strips of 2.4cm
\(\frac{48}{20}\) = 2.4
Is this width accurate?
Yes
Explanation:
The strip is equally divided without leaving any remainder.
\(\frac{48}{20}\) = 2.4 centimeter wide
Question 2.
James takes a ruler and measures the width of the piece of paper. He finds that the actual width is 48.8 centimeters. Find the width of each strip. How can you check if your answer is reasonable?
Answer:
2.44 cenimetres
Explanation:
The actual width is 48.8 centimeters
and it is cut in to 20 strips of equal pieces
\(\frac{48.8}{20}\) = 2.44 cm
Put on Your Thinking!
Challenging Practice
Solve. Show your work.
Question 1.
A plumber has two pipes. One pipe is 7 times as long as the other pipe. He cuts 2.2 meters from the longer pipe. The remaining length of this pipe is 3 times that of the shorter pipe. Find the length of the shorter pipe in meters.
Answer:
0.55 meters short.
Explanation:
One pipe is of length x
Other pipe length is 7x
7x – 2.2 =3x
7x – 3x = 2.2
4x = 2.2
x= 2.2
\(\frac{2.2}{4}\) = 0.55m
Question 2.
At a farmer’s market, 5 pounds of strawberries cost $21.50. At a supermarket, 3 pounds of the same quality strawberries cost $15.75.
a. Which is a better buy?
Answer:
At a farmer’s market is a better buy.
Explanation:
1 pound of strawberries cost $4.3
At farmer market,
5 pounds of strawberries cost $21.50
for 1 pound= \(\frac{21.50}{5}\) = $ 4.3
At supermarket
3 pounds of strawberries cost $15.75
for 1 pound= \(\frac{15.75}{3}\) = $ 5.25
b. How much can you save by buying 20 pounds of the strawberries that are the better buy?
Answer: $19
Explanation:
The difference between the farmer’s market cost and the supermarket cost is
$5.25 – $4.3 = $0.95 for one pound of strawberries
20 x $0.95 = $19
$19 save by buying 20 pounds of the strawberries that are the better buy
Put On Your Thinking!
Problem Solving
Solve. Show your work.
Question 1.
Sam buys 10 oranges and 11 apples for $10.05. The total cost of 1 orange and 1 apple is $0.94. How much does an apple cost?
Answer: $5.17
Explanation:
Cost of 1 orange and 1 apple is $0.94
\(\frac{0.94}{2}\) = $ 0.47
an apple cost = 11 * $0.47= $5.17
Question 2.
A bucket filled with sand has a mass of 11.15 kilograms. When it is filled with water, the mass is 5.95 kilograms. The mass of the sand is twice that of the water. Find the mass of the bucket in grams.
Answer: 400 grams
Explanation:
Mass of bucket filled with sand is 11.5 kg
Mass of bucket filled with water is 5.95 kg
It is given that the mass of sand is twice that of the water.
So if mass of water is x kg, then mass of sand is 2x kg.
Let the mass of bucket be y kg, then as per given condition we get,
2x+y=11.5 ....(1)
x+ y=5.95 ..….(2)
Subtract (2) from (1)
2x+y=11.5 x+ y=5.95 − − − x=5.55
Put this value in (2) to get,
5.55+y=5.95 y=5.95−5.55 y=0.4
So the mass of bucket in grams is 0.4×1000=400 grams.
Solve. Show your work.
Question 3.
The total capacity of 6 pitchers and 12 glasses is 21 liters. The capacity of a pitcher is 5 times that of a glass. Find the capacity of each glass. Give your answer in liters.
Answer:
The capacity of each glass is 0.5 liters.
Explanation:
one picture = 5 glass
Total capacity = 6 pitchers + 12 glasses = 21 liters
= 30 glasses + 12 glasses = 21 liters
= 42 glasses = 21 liters
So, 21/42 = 0.5 liters.
Solve. Show your work.
Question 4.
Dahlia has just enough money to buy either 6 pears and 20 oranges or 12 oranges and 11 pears. A pear costs $0.80. How much does an orange cost?
Answer:
Orange cost is $0.5
Explanation:
let Pear is p and Orange is q
6p + 20q = 11p + 12q
11p – 6p = 20q – 12q
5p = 8q
q = 5p/8
q = 5 x 0.80 / 8
q = $0.50